The aging process has multiple effects on the overall thickness and elasticity of the cells which comprise the skin. As skin ages, the amount of collagen produced is decreased and the type of collagen changes. In addition, the elastin in the skin decreases, the melanin granules collect into areas of dark-colored blemishes, the cells of the skin become older and the layers of expired cells increases. There are some remedies available to address these problems. Traditionally, retin-A is used to increase collagen production, decrease elastin loss, decrease production of metalloproteases (which may cause oxidative damage to the skin), disperse melanin granules and exfoliate the layers of dead skin cells from the skin. However, retin-A has some undesirable side effects and requires monitoring of sun exposure while treating skin. There are additional treatments for aging skin such as hydroquinone (bleaches skin and slows melanin production), alpha hydroxy acid (acts similar to retin-A), anti-oxidants (e.g. Cellex-C, Prevage or Revale). There is a continuing need for the development of skin care products that aid in the appearance of younger, more vibrant, healthy looking skin.
Vitiligo is an autoimmune disease presenting with progressive loss of skin pigmentation. Vitiligo is a cutaneous disease in which the melanocytes are destroyed in discrete patches, resulting in lightened areas of variable size and location distributed throughout the skin of the body. Melanocytes are cells located in the stratum basale (bottom layer) of the skin's epidermis. They are also located in the eye, ear, meninges, bones and heart. Melanocytes produce a pigment called melanin, a derivative of the amino acid tyrosine, through the process of melanogenesis. Variations in the activity of melanocytes and the production of melanin is a primary determinant of human skin color. The condition of vitiligo can also affect eye pigmentation and ear function, as melanin is expressed in both the ear and the uveal tract of the eye. The lightened lesions of the skin are immunocompromised and generally have greater susceptibility to the damaging effects of the sun, premature aging and possible cancer of the skin. The disease strikes about 1% of the world population, generally during teenage years. The progressive loss of melanocytes from depigmenting vitiligo skin is accompanied by cellular infiltrates containing T lymphocytes. Infiltrating cytotoxic T cells with high affinity T cell receptors have likely escaped clonal deletion in the thymus, allowing such T cells to enter the circulation. It is thought that through the expression of cutaneous lymphocyte antigen, these T cells home to the skin where they express type 1-cytokine profiles and mediate melanocyte apoptosis via the granzyme/perforin pathway. As this condition affects the skin and is readily visible to the public eye, there are many psychological and social problems that can result. Hence, there is a great need for continuing development of treatments that can be used to minimize the visible consequences of a condition such as vitiligo, as well as other conditions which manifest themselves as discolorations of the skin (aging spots, liver spots, etc.).